There’s a certain type of parental pride that grows from just the right combination of willful ignorance, unflagging optimism, and impressive mental gymnastics. Junior’s latest report card was less than stellar? Well, yes—he’s so smart that school just bores him. Little League game spent on the bench? The coach probably doesn’t realize the talent he has on his hands.

But that usually harmless denial can also manifest itself in a more significant—and more damaging—way, according to a new study in theJournal of the American Academy of Nutrition and Dietetics. Specifically, the study lent more support to the notion that parents of obese children often fail to see their kids’ weight as unhealthy, even after a doctor’s diagnosis.

Researchers from the University of California San Diego and Brown University surveyed parents of first-time patients at a pediatric obesity clinic, assessing the families’ willingness to help their children lose weight. The patients, who ranged in age from 5 to 20, had all been classified as overweight or clinically obese, and most had been referred to the clinic for treatment by their regular pediatricians.

The majority of parents, 93.5 percent, correctly recognized that their children were, in fact, overweight or obese—but nearly 30 percent said they didn’t see their children’s weight as a problem, and roughly the same number rated their children’s health as “very good” or “excellent.”

This dissonance, according to pediatrician and lead study author Kyung Rhee, may have to do with what she calls “the normalization of obesity.”

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“There are so many kids who are overweight—and so many adults who are overweight—that a lot of parents just don’t recognize it” as a problem, she says (around one-fifth of U.S. children and one-third of adults are currently obese, according to the Centers for Disease Control and Prevention).

In the same survey, parents were also asked about what changes they had made or planned to make to their children’s eating and exercise habits. Researchers then divided the parents into stages ranging from “precontemplation/contemplation” (those who were not yet thinking about making changes, or had only just begun) to “action/maintenance” (those who had already made lifestyle changes and kept them up for some time). Despite the fact that they filled out their surveys inside an obesity clinic, 40 percent of parents hadn’t yet made it to the action/maintenance stage in changing their children’s diets, while 60 percent hadn’t gotten around to encouraging more physical activity.

Though the study was based on only a small participant pool, past research has also pointed out this glaring parental blind spot: An analysis of 69 separate studies conducted between 1990 and 2012, published earlier this year in Pediatrics, concluded that more than half of all parents underestimate their children’s weight.

In the U.S., where the obesity rate has doubled among children (and quadrupled among teens) over the last 40 years, this lack of awareness has made its way down to the kids themselves. More than 40 percent of obese American kids are unaware they have a weight problem, the CDC recently announced.

The first step to getting overweight children on a healthier track, Rhee says, is getting their parents to take a healthier view of reality.

“Without parents’ involvement in this, it’s pretty difficult for kids to change,” she says. “In general, parents are the ones buying the food, parents are the ones setting the example.”

Giving up after-school Cheetos for celery stalks can be tough. Trading screen time for time outdoors can be even tougher. But this study is one more reminder than the most Herculean task may be getting parents to recognize a problem at all.